package adapters

import (
	"context"
	"errors"
	"log"
	"time"

	oppintel "github.com/missionworkforce/missionmatch/internal/modules/opportunity_intelligence"
	"github.com/missionworkforce/missionmatch/internal/platform/marketintel"
)

// USASpendingSource adapts the existing awards Provider to the OpportunitySource protocol with no change
// to its behavior. It paginates one award market query and yields one contract award record per result.
// A 429 stops the pull gracefully. The free USASpending provider is the default and stays the fallback
// once the SAM Contract Awards API adapter is added in Workstream B.
type USASpendingSource struct {
	prov    marketintel.Provider
	query   marketintel.AwardQuery
	pageCap int
	now     func() time.Time
}

// NewUSASpendingSource builds the adapter over an existing Provider and a market query. A pageCap of
// zero defaults to 5 pages, matching the standalone awards-sync.
func NewUSASpendingSource(prov marketintel.Provider, query marketintel.AwardQuery, pageCap int) *USASpendingSource {
	if pageCap <= 0 {
		pageCap = 5
	}
	return &USASpendingSource{prov: prov, query: query, pageCap: pageCap, now: time.Now}
}

// Name is the provenance label, taken from the underlying provider (for example USASpending).
func (u *USASpendingSource) Name() string { return u.prov.Name() }

// Fetch paginates the award market query and yields each award as a contract award record.
func (u *USASpendingSource) Fetch(ctx context.Context, yield func(oppintel.OpportunityRecord) error) error {
	now := u.now().UTC()
	q := u.query
	for page := 1; page <= u.pageCap; page++ {
		q.Page = page
		awards, hasNext, err := u.prov.FetchAwards(ctx, q)
		if err != nil {
			if errors.Is(err, marketintel.ErrThrottled) {
				log.Printf("awards source throttled on page %d, stopping the pull", page)
				return oppintel.ErrThrottled
			}
			return err
		}
		for _, a := range awards {
			if yerr := yield(fromAward(a, now)); yerr != nil {
				return yerr
			}
		}
		if !hasNext {
			break
		}
	}
	return nil
}